<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <link href="index3.css" rel="stylesheet" type="text/css">
</head>
<body>
  <p id="pid">hello css<a href="http://www.jikexueyuan.com">学院</a></p>
  <div id="divid">
      这是div<p>这是第一个div</p>
  </div>
</body>
</html>